The present invention relates to automatically re-cycling pneumatic pumps. More particularly, the present invention relates to a pneumatic mud pump which automatically begins pumping responsive to the reception by the pump apparatus of an inflow volume of mud, slurry or like fluid to be pumped. Even more particularly, the present invention relates to a pneumatic pumping apparatus for pumping drilling mud, and like thick, difficult to pump slurry fluids in which the valving member alternatively and sequentially seals the compressed air supply for pressurizing the pump and the gravity inflow for adding fluids to the pump, with the single compressed air source providing both instrumentation and pressure head pumping functions.
General Background and Prior Art
In the oil field industry, and especially associated with drilling platforms, drilling rigs and the like, it is known to use a thick viscous fluid known as drilling mud during the proper procedures for drilling wells. The use of drilling mud does produce some problems which are a by-product of its normal beneficial use to the rig. The mud used in drilling is quite thick and difficult to pump or move when it is used up. Waste mud frequently runs off the drilling platform to an area below the rig into what is known in the art as the rig cellar. From the rig cellar, the unwanted mud which is often polluted or too filthy to reclaim must be pumped to a holding pond or pit which is known in the art as a "reserve pit".
Pumps which are known in the art for the pumping of drilling mud and like heavy materials are generally a conventional impeller driven pump. These suffer in that they are inadequate or inefficient in pumping mud as the mud thickens. This is particularly a problem when the weather is quite cold and the mud becomes very thick and difficult if not impossible to transmit from the rig cellar to the reserve pit using conventional pumps. It is not unknown for an oilman or other drilling rig personnel to hand empty the rig cellar using a shovel and bucket when the drilling mud in the cellar becomes so thick that conventional pumps are ineffective in discharging the cellar of the mud and trash which collect there within. It is to this problem that the present invention is directed.